Fat digestion

Monday, November 9, 2020

Fat digestion



Fats are necessary macronutrients because they are the main energy source, are part of the cell membrane structure, provide essential fatty acids, constitute the vehicle for liposoluble vitamins, provide palatability and produces satiety.

Digestion takes place in an aqueous environment, the intestine, but the hydrophobic property of fats (are insoluble in water) makes the process difficult. Under physiological conditions, mechanical digestion after passing through the stomach, dietary fat, as triglycerides, is emulsified by bile salts and degraded by pancreatic lipases (enzymatic digestion). The resulting degradation products (mainly free fatty acids and monoglycerides) are surrounded by bile salts, oriented with the hydrocarbon tails (hydrophobic) inwards and heads (hydrophilic) facing outward, forming spherical structures called micelles, form in which these degradation products will be transported up to the apical membrane of the enterocytes for absorption.

But not all the fats are equal: its chemical composition determines their ability to solubilise forming micelles and therefore its digestibility. Obviously other factors such as the species and animal age and the characteristicsof the diet, but in general termsit can be said that:

    • In monogastrics animals, the length of the hydrocarbon chain hinders the digestibility of the fatty acids, whereas the same length, the degree of unsaturation (double bonds presence) facilitates it.

    • In ruminants the digestibility differences between the different types of fats are lower because rumen microorganismsare involved.

Enhance digestion is one of the challenges of the current production system, because the high cost of manufacture forced to carefully adjust the raw materials to optimise formulas looking for maximum performance. Either by the inability to digest (young animals) or by placing them at low levels in feed (layers and fattening pigs), we must help animals to take advantage of dietary fat, improving digestion and absorption in order to obtain the maximum energy. The way to achieve is by adding in the feed lysolecithins, modified phospholipids derived from soya.

Lysolecithins addition reduces the fat droplets size, promotes the hydrolysis and micelle formation and enhances intestinal permeability. All this results in higher digestibility of the feed, nutrients absorption and energy production. Lysolecithins are a very useful tool to reformulate, as they will allow to reduce the energy of the diet, and therefore economiseit, and to increasefarm performance.

Is advisable to use liquid lysolecithins against solid ones (powder) because besides being more pure and do not require handling by workers, they can be dosed by spraying together with fats in the mixer, which undoubtedlyenhances its effectiveness.


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Article made possible through the contribution of Adiveter